Diffusion Solder Preform Microstructure for Lower-Temperature Joining
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Solution Overview
Problem
The existing methods for forming diffusion solder connections require high precision and manufacturing effort, with limitations on diffusion path length and thermal strain, making them costly and time-consuming, and often necessitate elevated temperatures and specific surface cleanliness.
Innovation Solution
A solder preform with a microstructure comprising a solder material phase and a metallic material phase, where a diffusion zone forms between the phases, allowing for a controlled distance between the diffusion zone and the joining surfaces, enabling rapid formation of an intermetallic compound at lower temperatures and reduced thermal strain, facilitating easier handling and assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solder preform without pre-formed diffusion zone is used, then the manufacturing process is simpler, but the diffusion path is too long and thermal strain increases
Solution Approach 1:
The patent applies preliminary action by pre-forming a diffusion zone within the solder preform before the actual joining process. This pre-formed diffusion zone contains intermetallic compounds that will facilitate and accelerate the diffusion process during soldering, effectively reducing the diffusion path length and thermal strain during the actual joining operation while maintaining manufacturing simplicity.
2Productivity
If elevated temperatures are used for diffusion soldering, then the diffusion process is faster, but thermal strain on joining partners increases
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical composition of the solder preform. Specifically, it incorporates a pre-formed diffusion zone with specific intermetallic compound concentrations and phases that enable effective diffusion soldering at reduced temperatures. This compositional parameter change allows achieving adequate diffusion rates without requiring elevated temperatures that would cause excessive thermal strain on the joining partners.
3Ease of operation
If conventional soldering procedures are used, then the process is easier to handle, but the diffusion zone formation is insufficient
Solution Approach 1:
The patent applies the intermediary principle by introducing a specially designed solder preform with a pre-formed diffusion zone as an intermediary element between the two joining partners. This intermediary preform contains pre-formed intermetallic compounds that act as a mediator to facilitate reliable diffusion zone formation during conventional soldering procedures, bridging the gap between easy handling and reliable diffusion zone formation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the formation of a reliable diffusion solder connection with reduced processing time and thermal stress, enabling the use of conventional soldering procedures and improving the mechanical and thermal stability of the connection.
Implementation Method 1
a diffusion zone (19) consisting of the material of the first phase (20) and the material of the second phase (18) is formed in the solder preform
Data Source
AI summary
Various embodiments include a solder preform for establishing a diffusion solder connection comprising: a microstructure including a solder material and a metallic material; a first joining surface for a first joining partner and a second joining surface for a second joining partner; and a diffusion zone comprising an intermetallic compound of at least some of the solder material and at least some of the metallic material. The first joining surface and the second joining surface include at least some solder material.